Indirect methods for assessing road friendliness of lorry suspensions

Two methods for assessing the road damaging potential of heavy vehicles are described in this paper. The methods use a simple laboratory test to characterize vehicle dynamics. This information is then used to predict the dynamic tyre forces generated by the vehicle for typical highway conditions. A quarter car laboratory test rig fitted with a leaf spring suspension is used to investigate these methods. Step inputs are used to excite the rig, and various sensors measure the response. A linear technique using the convolution algorithm is investigated initially. A non-linear method using parameter estimation is then examined. The accuracy of both systems is determined by comparing tyre force data measured on the test rig with predicted tyre forces.